From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-10.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id DCD0AC2D0C6 for ; Fri, 27 Dec 2019 18:03:57 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id B842C206F4 for ; Fri, 27 Dec 2019 18:03:57 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1577469837; bh=15uCv88DqOg4sbjIuVZMtUhC1JnMrYLSD4Kpcggr87k=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=D57zZg2+YQlyh27LoDjX47p9TKFoDZ90U+yLpG7/8B1oyePSNgG9KwTVrKgoMjFDC AmV/wsEFKK1hcZbSMG8fq5KwSqxL0XbjNYOqChBX6Bq4LqPFzUe8fIiJCIs5msfKub nk2o6WvTLQ0TP961Zoj+5t2ciDm2/WITR7TBneoE= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728789AbfL0SD4 (ORCPT ); Fri, 27 Dec 2019 13:03:56 -0500 Received: from mail.kernel.org ([198.145.29.99]:60618 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728659AbfL0SDY (ORCPT ); Fri, 27 Dec 2019 13:03:24 -0500 Received: from sasha-vm.mshome.net (c-73-47-72-35.hsd1.nh.comcast.net [73.47.72.35]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 93AC221582; Fri, 27 Dec 2019 18:03:22 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1577469803; bh=15uCv88DqOg4sbjIuVZMtUhC1JnMrYLSD4Kpcggr87k=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=HpggWsSgIFLD5W865PYYaDwNfcF8dzY7VDmOmj8S5M6jeUX3zYirGoJ6r0QwiGYdn DDgeN0m8M/hGxF5oYIO1xYG0P4R5DCr8G50hYvN+ANrFr3TpjXzvN+KAW/OXcOcizp ETYnFq9tokA0NBxcg66eSa2SKQ2+pa/A1aOLCDg0= From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: =?UTF-8?q?Jan=20H=C3=B6ppner?= , Cornelia Huck , Peter Oberparleiter , Stefan Haberland , Jens Axboe , Sasha Levin , linux-s390@vger.kernel.org Subject: [PATCH AUTOSEL 4.14 50/57] s390/dasd/cio: Interpret ccw_device_get_mdc return value correctly Date: Fri, 27 Dec 2019 13:02:15 -0500 Message-Id: <20191227180222.7076-50-sashal@kernel.org> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20191227180222.7076-1-sashal@kernel.org> References: <20191227180222.7076-1-sashal@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Jan Höppner [ Upstream commit dd4b3c83b9efac10d48a94c61372119fc555a077 ] The max data count (mdc) is an unsigned 16-bit integer value as per AR documentation and is received via ccw_device_get_mdc() for a specific path mask from the CIO layer. The function itself also always returns a positive mdc value or 0 in case mdc isn't supported or couldn't be determined. Though, the comment for this function describes a negative return value to indicate failures. As a result, the DASD device driver interprets the return value of ccw_device_get_mdc() incorrectly. The error case is essentially a dead code path. To fix this behaviour, check explicitly for a return value of 0 and change the comment for ccw_device_get_mdc() accordingly. This fix merely enables the error code path in the DASD functions get_fcx_max_data() and verify_fcx_max_data(). The actual functionality stays the same and is still correct. Reviewed-by: Cornelia Huck Signed-off-by: Jan Höppner Acked-by: Peter Oberparleiter Reviewed-by: Stefan Haberland Signed-off-by: Stefan Haberland Signed-off-by: Jens Axboe Signed-off-by: Sasha Levin --- drivers/s390/block/dasd_eckd.c | 9 +++++---- drivers/s390/cio/device_ops.c | 2 +- 2 files changed, 6 insertions(+), 5 deletions(-) diff --git a/drivers/s390/block/dasd_eckd.c b/drivers/s390/block/dasd_eckd.c index 0d5e2d92e05b..81359312a987 100644 --- a/drivers/s390/block/dasd_eckd.c +++ b/drivers/s390/block/dasd_eckd.c @@ -1133,7 +1133,8 @@ static u32 get_fcx_max_data(struct dasd_device *device) { struct dasd_eckd_private *private = device->private; int fcx_in_css, fcx_in_gneq, fcx_in_features; - int tpm, mdc; + unsigned int mdc; + int tpm; if (dasd_nofcx) return 0; @@ -1147,7 +1148,7 @@ static u32 get_fcx_max_data(struct dasd_device *device) return 0; mdc = ccw_device_get_mdc(device->cdev, 0); - if (mdc < 0) { + if (mdc == 0) { dev_warn(&device->cdev->dev, "Detecting the maximum supported data size for zHPF requests failed\n"); return 0; } else { @@ -1158,12 +1159,12 @@ static u32 get_fcx_max_data(struct dasd_device *device) static int verify_fcx_max_data(struct dasd_device *device, __u8 lpm) { struct dasd_eckd_private *private = device->private; - int mdc; + unsigned int mdc; u32 fcx_max_data; if (private->fcx_max_data) { mdc = ccw_device_get_mdc(device->cdev, lpm); - if ((mdc < 0)) { + if (mdc == 0) { dev_warn(&device->cdev->dev, "Detecting the maximum data size for zHPF " "requests failed (rc=%d) for a new path %x\n", diff --git a/drivers/s390/cio/device_ops.c b/drivers/s390/cio/device_ops.c index b22922ec32d1..474afec9ab87 100644 --- a/drivers/s390/cio/device_ops.c +++ b/drivers/s390/cio/device_ops.c @@ -595,7 +595,7 @@ EXPORT_SYMBOL(ccw_device_tm_start_timeout); * @mask: mask of paths to use * * Return the number of 64K-bytes blocks all paths at least support - * for a transport command. Return values <= 0 indicate failures. + * for a transport command. Return value 0 indicates failure. */ int ccw_device_get_mdc(struct ccw_device *cdev, u8 mask) { -- 2.20.1